void main(List<String> args) {
  Persion persion = new Persion("name", 1);
  print(persion.name);
  print(persion.age);
}

class Persion {
  String? name;
  int? age;
  // Persion(String name, int age) {
  //   this.age = age;
  //   this.name = name;
  // }
  // dart语法糖构造方法
  Persion(this.name, this.age);
}
